How do you close the end of a ridge cap on a metal roof?
Short answer. The open end of a metal ridge cap at a gable is closed either with a preformed end cap sized to the ridge profile or by notching and folding the cap's end down over the rake trim, with outside foam closures and butyl tape inside the ridge in both cases. The goal is a sealed end that sheds wind-driven rain and keeps wasps and birds from nesting in the hollow.
Option 1: preformed end cap
A stamped or formed piece matched to the ridge profile slips into or over the ridge end and is riveted or screwed in place with sealant behind it. It looks tidy and goes on quickly, but it must match the exact ridge shape and color.
Option 2: notch and fold
The installer cuts small reliefs in the ridge cap so its end can be bent down and folded over the rake trim, closing the end with the cap's own metal. Sealant goes into the folds. It takes skill but leaves no extra parts to loosen.
Inside the ridge
- Outside foam closures sit on the panels under the ridge cap, sealing the ribs. Vented closures are used if the ridge exhausts attic air.
- Butyl tape above and below the closures makes the joint watertight.
- Fasteners go through the ridge cap into the ribs or seams at the manufacturer's spacing.
Where rake meets ridge
The rake trim should run up under the ridge cap end so water flows over the joint, not into it. The end cap or fold then covers the top of the rake trim.
Signs of a bad ridge end
- Daylight visible inside the ridge end from the ground.
- Wasp or bird activity at the gable peak.
- Drips or stains near the gable wall in the attic after wind-driven rain.